首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   836篇
  免费   97篇
  国内免费   9篇
耳鼻咽喉   37篇
儿科学   45篇
妇产科学   3篇
基础医学   44篇
口腔科学   12篇
临床医学   103篇
内科学   157篇
皮肤病学   19篇
神经病学   102篇
特种医学   171篇
外科学   94篇
综合类   11篇
现状与发展   1篇
一般理论   1篇
预防医学   71篇
眼科学   4篇
药学   19篇
肿瘤学   48篇
  2023年   25篇
  2021年   10篇
  2020年   20篇
  2019年   10篇
  2018年   23篇
  2017年   27篇
  2016年   25篇
  2015年   14篇
  2014年   24篇
  2013年   19篇
  2012年   16篇
  2011年   11篇
  2010年   17篇
  2009年   24篇
  2008年   21篇
  2007年   20篇
  2006年   18篇
  2005年   31篇
  2004年   12篇
  2003年   18篇
  2002年   14篇
  2001年   26篇
  2000年   13篇
  1999年   21篇
  1998年   20篇
  1997年   11篇
  1995年   13篇
  1994年   23篇
  1993年   16篇
  1992年   31篇
  1991年   21篇
  1990年   19篇
  1989年   27篇
  1988年   21篇
  1987年   29篇
  1986年   16篇
  1985年   22篇
  1984年   22篇
  1983年   21篇
  1982年   10篇
  1981年   16篇
  1980年   13篇
  1979年   15篇
  1978年   14篇
  1977年   11篇
  1976年   16篇
  1975年   17篇
  1972年   9篇
  1971年   7篇
  1970年   7篇
排序方式: 共有942条查询结果,搜索用时 15 毫秒
1.
Toxic shock syndrome has been associated with rhinologic surgery and medical devices, and it has been linked to a circulating exotoxin of a toxogenic strain of Staphylococcus aureus. One hundred forty patients with rhinosinusitis were studied. Nasal cultures were obtained. The microbiological characteristics are described. The carrier rate for Staphylococcus aureus was 35%. Thirty percent of patients selected for surgery were Staphylococcus aureus carriers. Toxin-capable isolates were identified in 40% of those tested. Users of cocaine, topical decongestants, and steroid sprays had a statistically higher rate of Staphylococcus aureus carriage compared to non-users. It is hoped that by identifying the population at risk and defining the factors associated with the development of toxic shock syndrome, a cogent policy of prevention can be established.  相似文献   
2.
Primary megaureter is a common cause of obstructive uropathy in children. The imaging studies and records of 75 infants and children with primary megaureter seen at Children's Hospital were reviewed. We describe our findings and illustrate the clinical presentations, diagnosis, and treatment of this entity.  相似文献   
3.
4.
5.
腹部外科常见感染性疾病的病原菌及药敏试验研究   总被引:1,自引:0,他引:1  
为了了解本地区本医院腹部外科感染性疾病病原菌的构成比和药物敏感率的变化,指导临床用药,我们采用美国BD公司生产的6B和7D两种增菌瓶采集标本和培养细菌,并用该公司生产的生化板和药敏板,对1994~1996年269例常见的普外科感染性疾病患者的手术标本进行前瞻性的细菌培养和药敏试验研究.  相似文献   
6.
The question is addressed whether antigens of Leishmania, a parasite residing in the endosomal compartment of macrophages, can be presented in the context of major histocompatibility complex class I molecules. We used E. coli β-galactosidase as a model antigen which can be expressed in high levels in L. mexicana promastigotes (L. mexicana-gal). Infection of BALB/c mice with L. mexicanagal induces β-galactosidase-specific cytotoxic T cells (CTL), which can be isolated using a β-galactosidase-expressing mastocytoma line as an antigen-presenting cell. These CTL recognize epitopes of β-galactosidase in the context of H-2Kd; however, they do not recognize L. mexicanagal-infected macrophages even after killing of the intracellular amastigotes by drug treatment or macrophage activation by lymphokines, although class I-peptide interaction and the presentation of endogenously produced antigens is normal. It is concluded that parasite antigens can induce a CTL response in vivo but that these CTL cannot recognize infected macrophages because the relevant epitopes cannot gain access to class I molecules. The effect of priming in vivo may be explained by the well-known but ill-understood phenomenon of cross-priming.  相似文献   
7.
Relationships between estimated "tar" exposure from current and past cigarette consumption, were related to respiratory symptoms and function during the seventh survey (1981-1983) of the Tucson epidemiologic study of airways obstructive diseases. Smokers (n = 582; 280 males and 302 females) and exsmokers (n = 621; 345 males and 276 females), answered detailed questions on current and past smoking, and performed flow-volume maneuvers. Cough and phlegm were significantly associated with estimated "tar" exposure from current cigarette consumption. Cough, phlegm, and dyspnea were associated with reported deep inhalation in both sexes, while wheeze was so associated in females. In young smokers (less than 35 years), symptoms were more prevalent in those who had predominantly smoked cigarettes with estimated high "tar." Total exposure was more important in older smokers. Generally, exsmokers showed a lower prevalence of symptoms than smokers. Cross-sectional lung function measurements were significantly related to total estimated "tar" exposure and age. Multiple logistic regressions provided models which helped predict symptoms and lung function impairment in smokers and exsmokers on the basis of estimated "tar" exposure and pack-years of smoking.  相似文献   
8.
Longitudinal changes in FEV1 (delta FEV1) have been examined in a sample of the general population of Tucson, Arizona. Adults with satisfactory spirometric tests in all 7 surveys performed over a period of 11 yr showed some between-survey differences in mean FEV1. Although small in absolute magnitude, such survey biases (which would be impossible to detect unless multiple spirometric tests were carried out on a relatively large group of subjects) could have a marked effect on calculated changes in FEV1 and may explain the widely divergent delta FEV1 values reported in the literature. After adjusting for survey biases, the relationships of delta FEV1 to age, sex, and body size were examined in "healthy" nonsmokers in the population who were followed for an average of 9.6 yr. The FEV1 showed an accelerating decline with age, and delta FEV1 was best explained by a model of proportional change in which it is a function of Age X Height3. Longitudinally determined delta FEV1 showed much less decline in function and a later apparent age of onset of decline than suggested by cross-sectional analyses. While small "learning effects" in longitudinal calculations cannot be excluded, most of the cross-sectional versus longitudinal differences are probably ascribable to past events that have adversely affected the FEV1 in older adults, thereby increasing cross-sectional age effects. Present findings also suggest that generally applicable "prediction equations" for delta FEV1 probably cannot be developed and that delta FEV1 values should only be compared between groups studied in an identical manner within a given study.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
Hunter syndrome is one of a heterogeneous group of recessively inherited mucopolysaccharide storage diseases (MPS) with similar biochemical defects manifested by impairments in muco-polysaccharide catabolism with variable but progressive clinical courses. Abnormal accumulation and deposition of mucopoly-saccharides in the tissues of several organs lead to numerous anatomical, musculoskeletal and neurological abnormalities which are known to complicate anaesthetic and airway management. Hunter syndrome has a wide variance of clinical phenotypes ranging from mild to severe. We present a patient having physical and neurological features consistent with a severe clinical presentation of Hunter syndrome (MPS, Type II). Following a seemingly uneventful intraoperative anaesthetic course including isoflurane, nitrous oxide and fentanyl (0.93 μg · kg−1), resumption of spontaneous ventilation and return to consciousness were delayed until intravenous naloxone (200 μg) was administered 100 min after the opioid administration. The cause of delayed recovery from anaesthesia in this patient is unknown. La maladie de Hunter fait partie du groupe des affections hétérogènes héréditaires et récessives des mucopolysaccharidoses (MPS) avec lesquelles elle partage les mêmes anomalies biochimiques. Celles-ci se manifestent par des altérations du catabolisme des mucopolysaccharides et une évolution variable et progressive. L’accumulation anormale de mucopolysaccharides dans les tissus de plusieurs organes provoque de nombreuses lésions musculo-squelettiques et neurologiques qui compliquent la gestion de l’anesthésie et des voies aériennes. Les phénotypes cliniques de la maladie de Hunter varient de légers à graves. Cette observation porte sur un patient qui présente des manifestations cliniques graves de la maladie de Hunter (MPS type II). A la suite d’une anesthésie sans problèmes réalisée avec de l’isoflurane, du protoxyde d’azote, et du fentanyl (0,93 μg · kg−1), le retour normal à la ventilation spontanée et à la conscience est retardé jusqu’à l’administration de naloxone (200 mg) iv effectuée 110 min après le morphinique. La raison de ce retard est inconnue.  相似文献   
10.
The objective of the National Human Exposure Assessment Survey (NHEXAS) in Arizona is to determine the multimedia distribution of total human exposure to environmental pollutants in the classes of metals, pesticides, and volatile organic compounds (VOCs) for the population of Arizona. This was accomplished by studying a probability-based sample of the total population in Arizona with a nested design for the different stages of sampling (954 Stage I, 505 Stage II, and 179 Stage III participants). This report compares the study population demographics with those from the U.S. Census and provides preliminary data on the distributions of the example pollutant for each class, lead for metals, chlorpyrifos for pesticides, and benzene for metals. The probability-based sample age and gender demographics compare reasonably well with the Census data (1990 Census and 1996 Census Estimate). The race/ethnicity compared less well with 21% Hispanics in the 1996 Census Estimate and 42% Hispanics in the entire NHEXAS-Arizona sample and 30% Hispanics as Stage III participants for this study. The chemical analyses of the various media (yard soil, foundation soil, house dust, indoor air, outdoor air, drinking water, food, and beverage) show generally low levels of the representative pollutants. The 50th percentiles of the distributions are generally near or below the analytical detection limits, and applicable Federal action limits were rarely exceeded.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号